Dispersion Effects in Nucleon Polarisabilities

Abstract

We present a formalism to extract the dynamical nucleon polarisabilities defined via a multipole expansion of the structure amplitudes in nucleon Compton scattering. In contradistinction to the static polarisabilities, dynamical polarisabilities gauge the response of the internal degrees of freedom of a composed object to an external, real photon field of arbitrary energy. Being energy dependent, they therefore contain additional information about dispersive effects induced by internal relaxation mechanisms, baryonic resonances and meson production thresholds of the nucleon. We give explicit formulae to extract the dynamical electric and magnetic dipole as well as quadrupole polarisabilities from low energy nucleon Compton scattering up to the one pion production threshold and discuss the connection to the definition of static nucleon polarisabilities. As a concrete example, we examine the results of leading order Heavy Baryon Chiral Perturbation Theory for the four leading spin independent iso-scalar polarisabilities of the nucleon. Finally, we consider the possible r{ô}le of energy dependent effects in low energy extractions of the iso-scalar dipole polarisabilities from Compton scattering on the deuteron.

17 pages LaTeX2e with 2 figures, using includegraphicx (5 .eps files). Minor corrections, references updated. Contents identical to version to appear in Phys. Rev. C 65, spelling different

References in corpus (3)

• Generalized dipole polarizabilities and the spatial structure of hadrons
• Compton Scattering by the Proton
• Nucleon Polarisabilities from Compton Scattering on the Deuteron

Cited by in corpus (20)

• Chiral Perturbation Theory and Baryon Properties
• Dispersion relations in real and virtual Compton scattering
• Using effective field theory to analyse low-energy Compton scattering data from protons and light nuclei
• Compton scattering from the proton in an effective field theory with explicit Delta degrees of freedom
• Signatures of Chiral Dynamics in Low Energy Compton Scattering off the Nucleon
• Hadron Polarizabilities
• Predictions of covariant chiral perturbation theory for nucleon polarisabilities and polarised Compton scattering
• Dispersion Theory in Electromagnetic Interactions
• Spin Polarizabilities of the Nucleon from Polarized Low Energy Compton Scattering
• Explicit Delta(1232) Degrees of Freedom in Compton Scattering off the Deuteron
• Proton scalar dipole polarizabilities from real Compton scattering data, using fixed-t subtracted dispersion relations and the bootstrap method
• First extraction of the scalar proton dynamical polarizabilities from real Compton scattering data
• Nucleon Polarizabilities from Deuteron Compton Scattering within a Green's-Function Hybrid Approach
• Comprehensive Study of Observables in Compton Scattering on the Nucleon
• Dynamical Polarizabilities of SU(3) Octet of Baryons
• Nucleon polarizabilities in covariant baryon chiral perturbation theory with explicit $\Delta$ degrees of freedom
• Nucleon Polarisabilities from Compton Scattering off the One- and Few-Nucleon System
• Computer Based Analytical Simulations of the Chiral Hadronic Processes
• Nucleon Spin-Polarisabilities from Polarisation Observables in Low-Energy Deuteron Compton Scattering
• van der Waals and Casimir-Polder interactions between neutrons